Pif1p helicase, a catalytic inhibitor of telomerase in yeast

J. Q. Zhou, E. K. Monson, S. C. Teng, V. P. Schulz, V. A. Zakian

Research output: Contribution to journalArticlepeer-review

200 Scopus citations


Mutations in the yeast Saccharomyces cerevisiae PIF1 gene, which encodes a 5'-to-3' DNA helicase, cause telomere lengthening and a large increase in the formation rate of new telomeres. Here, we show that Pif1p acts by inhibiting telomerase rather than telomere-telomere recombination, and this inhibition requires the helicase activity of Pif1p. Overexpression of enzymatically active Pif1p causes telomere shortening. Thus, Pif1p is a catalytic inhibitor of telomerase-mediated telomere lengthening. Because Pif1p is associated with telomeric DNA in vivo, its effects on telomeres are likely direct. Pif1p-like helicases are found in diverse organisms, including humans. We propose that Pif1p-mediated inhibition of telomerase promotes genetic stability by suppressing telomerase-mediated healing of double-strand breaks.

Original languageEnglish (US)
Pages (from-to)771-774
Number of pages4
Issue number5480
StatePublished - Aug 4 2000

All Science Journal Classification (ASJC) codes

  • General


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